This project, known as ATHENA, included two major components: (1) We conducted a randomized controlled trial of patient-specific recommendations about drug therapy for hypertension, delivered to primary care clinicians at the time of primary care clinic visits. The recommendations were based on VA Hypertension Guidelines. The trial included 36 clinicians and 4500 hypertensive patients enrolled in primary care clinics at VA Palo Alto Health Care System. We compared a general intervention to an individualized intervention. Both the general and the intervention groups of clinicians received extensive guideline education, as part of a VISN-mandated hypertension guideline implementation. Clinicians randomized to the individualized intervention received, in addition, computer-generated patient-specific recommendations about drug therapy of hypertension, delivered to the clinics with the encounter forms for each visit. (2) In the 2nd major component of the study, we collaborated with Stanford Medical Informatics to develop a hypertension decision support system (ATHENA DSS). ATHENA DSS combines detailed patient information from the VA electronic medical record (VistA) with hypertension guideline knowledge based on the VA and JNC 6 hypertension guidelines. A special feature of ATHENA DSS is that the knowledge in the system can be easily browsed and updated by clinician-managers, so that knowledge can be kept up to date with emerging clinical trial findings about best treatments. We developed an infrastructure to implement the system in a pop-up window in the CPRS-GUI in the primary care clinics at VA Palo Alto. We also conducted an offline test of the program logic by comparing the ATHENA DSS recommendations with those made by a physician for 100 randomly selected VA patients.